Iran’s IRNA news agency said Britain's top diplomat arrived and Zarif also discussed ways of ending the war in Yemen, where Iran is accused of supplying weapons to Shi’ite Huthi rebels. Tehran denies the allegation.

There was no immediate comment from the Britain Foreign Ministry on the discussions.

During his visit, Hunt will also meet Ali Shamkhani, secretary of Iran's Supreme National Security Council, according to Iranian state TV.

Zaghari-Ratcliffe, a project manager with the Thomson Reuters Foundation, is serving a five-year jail sentence for allegedly plotting to overthrow Iran's clerical establishment, a charge she and her family have denied.

"I arrive in Iran with a clear message for the country's leaders: putting innocent people in prison cannot and must not be used as a tool of diplomatic leverage," Hunt said in a statement before leaving London.

British officials have routinely sought Zaghari-Ratcliffe’s release in talks with Iranian leaders.

Hunt's visit to Iran is the first by a Western foreign minister since the United States in May withdrew from the 2015 Iran nuclear agreement between Tehran and world powers, saying the terms of the accord were not strict enough to prevent Iran from developing nuclear weapons. It also accuses Tehran of supporting militant violence in the region and other “malign” activities. Iran denies the allegations.

Washington in August started imposing crippling economic sanctions on Iran that were lifted in exchange for curbs on the country's nuclear activities.

Earlier this month, the U.S. administration targeted Iran’s energy, shipping, shipbuilding, and financial sectors, while the world's biggest interbank transfer network, SWIFT, announced it was cutting off links with “certain Iranian banks' access," further isolating Iran from the international financial system.

Iran continues to abide by the 2015 nuclear agreement, and Britain and other European nations have been trying to salvage the accord.

Hunt, in its statement ahead of his visit, said the deal was “a vital component of stability in the Middle East” and Britain would “stick to our side of the bargain as long as Iran does.”

"But we also need to see an end to destabilizing activity by Iran in the rest of the region if we are going to tackle the root causes of the challenges the region faces," he also said.